Legacy compatibility is not an issue (unless it makes things complicated, unreliable or limited in the name of backward compatibility). Lack of modern functionality is.
Similarly, presence IPv4 support in devices is not a problem - lack of IPv6 support is. The comparable issue would be if you have bought a new motherboard but all it supports is VGA - now, that'd be quite inconvenient (even if it's a server board that runs headless 99.99% of the time).
Fortunately, most of server boards have a built-in LOM solution with some sort of IP-KVM. So the actual video output is only ever needed for the very first time - and that's if LOM defaults are not known.
Or, well, if things break - e.g., I've had issues because management port sharing was enabled by default and I haven't realized I should turn it off until I've noticed that my server became unresponsive for IPMI-over-IP queries.
I'm a bit frustrated that I had to purchase an adapter, but at least that was an one-in-a-lifetime purchase.
You probably bought a server motherboard, so the ports are there for old KVM-type devices. Good luck buying a consumer motherboard with VGA and PS/2 ports.
Here you go. It's a little older, but AM4 is still competitive, especially if you're using video from the CPU. In which case, the lack of a 500 series chipset isn't a big limitation.
Depending on the rules there's also the https://www.asus.com/motherboards-components/motherboards/pr... with ps/2 and while there is no physical VGA you can passive adapter one out of the DisplayPort connector.
If it were passive, I'd say it counts (maybe some board connected vga to the dvi-a pins?), but I not the OP.